Disclosed herein are methods and apparatus for a printing system that includes a fusing member and a pressure member. More particularly, the disclosure relates to improved self-stripping of a print media from the fusing member as the media leaves a nip formed between the fusing member and pressure member.
In the art of xerography or other similar image reproducing arts, a latent electrostatic image is formed on a charge-retentive surface, i.e., a photoconductor or photoreceptor. To form an image on the charge-retentive surface, the surface is first provided with a uniform charge, after which it is exposed to a light or other appropriate image of an original document to be reproduced. The latent electrostatic image thus formed is subsequently rendered visible by applying any one of numerous toners specifically designed for this purpose.
In a typical xerographic device, the toner image formed is transferred to an image receiving media such as paper. After transfer to the image receiving media, the image is made to adhere to the media using a fuser apparatus. To date, the use of simultaneous heat and contact pressure for fusing toner images has been the most common system that utilizes a pair of pressure-engaged rolls. At the time of initial set-up of a xerographic device, the fuser system is set to be within certain specifications for nip width, media velocity and deformation of rolls and fusing belt or creep.
Nip width is one of the more significant drivers of image fix and quality. Media velocity is an important factor in paper handling. Deformation or creep, which is the release surface's extension in the nip, is important with respect to enabling the stripping of the paper from the fusing belt in a fusing system. It is known that higher magnitudes of creep are effective in improving the self-stripping capabilities of the fuser system over wide latitude of substrate media. Unfortunately, higher magnitudes of creep also mean higher levels of strain energy in the fuser roll materials when in the nip vicinity, thereby shortening the longevity of the belt and rolls and impacting print quality.
Additionally, usage of the belt and rolls in the course of normal printing activities causes contamination and increases the coefficient of friction between the rolls and the belt. This increase in the coefficient of friction reduces the self-stripping capabilities of the roll belt system over wide latitude of print media.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an improved method and apparatus for improving the self-stripping capabilities of a belt roll fuser system in a printing system.